Campbell diagram for 5MW turbine rotor

Dear Jason,

Thank you very much for your replay. It was so hepful for me. now i have the right result.

Best Regard
Amadou

Dear Jason,

I have somee questions about natural frequencys. i want to identify that in nonlinear model with FFT and compare with my result off Campbell diagram. But it is dificult to find out frequency. for the exitation i found some thing about “with white noise (e.g., broadband turbulence)” in your older posts. my question is, can i add the noise on the control input like Torq control oder there is a file for broadband turbulence in FAST? also i don’t know if i can found all frequency on each output of FAST. her you can find a data with a noise example.

best regards
Amadou
Noise.PNG

Dear Amadou,

I don’t think you’ll get the response you desire by adding white noise to the controller commands.

You may be able to get enough broadband excitation from normal turbulent wind created by TurbSim (nwtc.nrel.gov/alphas) is set-up to support user-specified spectra, which you could then set up to specify your own banded white-noise spectra.

For offshore systems, the HydroDyn module of FAST has a built-in option for specifying banded white noise incident waves.

Best regards,

Dear Jason,

Thank you for this explanation. Now i have to understand how TurbSim works.

Best regards
Amadou

Dear Jason,

I applied an FFT on my 5MW Turbine. Finaly the best result was without any exitation. Now i get all natural frequency. But for Drivetrain i get 0.69Hz when the rotor is spining at 12 rpm. I expected 1,7Hz like in campbell diagram. is there everiything wrong in my FFT?

Best regard
Damba

Dear Damba,

I would expect a lower drivetrain frequency only when the generator degree of freedom (DOF) is disabled (fixed-free condition). When the generator DOF is enabled (free-free condition), I would expect a drivetrain frequency around 1.7 Hz.

Best regards,

Dear Jason,

Thanks for your replay. in my case the generator degree of freedom(GenDOF) is disabled. only the FlapDOF1, FlapDOF2 and DrTrDOF are enabled. That would mean i have fixed-free condition and the frequencys will be 0,69Hz for drivetrain, 0,79Hz for FlapDOF1 and 2,3Hz for FlapDOF2. Am i right?

Best regards,
Damba

Dear Damba,

Yes, that sounds about right.

Best regards,

Dear Jason,

Thanks for the confirmation of my supposition.

Best regard
Damba

Dear Jason,

I try to run FAST8.v12 S-Function in real time simulator OPAL RT, which is working in Linux system. Therefore i did some changes in FAST to adapt the model to the Linux. Now my model works well with the Controll modes 1 and 3. But if i want to use my own controller from simulink(mode PCMode=4, VSContrl=4) i get the following error:

‘FAST_InitializeAll:SrvD_Init:PCMode can only equal 4 when ServoDyn is interfaced with Simulink or LabVIEW. Set PCMode to 0, 3, or 5 or interface ServoDyn with Simulink or LabVIEW.’

‘FAST_InitializeAll:SrvD_Init:VSContrl can only equal 4 when ServoDyn is interfaced with Simulink or LabVIEW. Set VSContrl to 0, 1, 3, or 5 or interface ServoDyn with Simulink or LabVIEW.’

It seems like the linux system don’t reconize my controller from simulink. I don’t know wich File is related to the Controll mode of Simulink so that i can do some modifications for Linux system.

Best regards
Damba

Dear Damba,

I’m assuming you recompiled FAST for use in Simulink? When doing so, set the compiler directive COMPILE_SIMULINK to avoid getting that error.

Best regards,

Dear Jason,

Thank you for your replay. Yes i recompiled FAST. I will set the compiler directive in the next days.

Best regards
Damba

Dear Jason,

I must rectify my declaration before: i just recompiled FAST without changing for Simulink. Now i found that COMPILE_SIMULINK is involved in the files ServoDyn.f90, FAST_Mods.f90 and FAST_Subs.f90. I don’t know how to set it. could you give me some directives to do that please?

Best regards
Damba

Dear Damba,

I don’t know what compiler you are using, but you should set the COMPILE_SIMULINK preprocessor directive in your linker dependencies. The FAST ReadMe file explains how to do this when using Intel Fortran with Visual Studio: wind.nrel.gov/nwtc/docs/README_FAST8.pdf.

Best regards,

Dear Jason,

Thanks for the replay and file. The compiler i am using is gfortran/gcc. i think my problem is that my FAST is running on Window and Linux at the same time. My new FAST doesn’t contain the “dependencies” order any more. I recompiled to obtaine the FAST_Library_glin32.so and some modifications in FAST_SFunc.c for linux.
for window system the control from simulink is working well. But the same control mode doesn’t work on Linux computer with the same recompiled FAST. Maybe i have to include the “dependencies” again.

Best Regards
Damba

Dear Damba,

I’m sorry, but I don’t personally have experience with the gfortran/gcc compiler. I suggest you review the documentation of that compiler to figure how to set compiler directives.

Best regards,

Dear Jason,

You are right. I have to know more about recompiling FAST.

Best regards,

Dear all,

I derived the natural Eigenfrequencies for the OC3-Hywind FOWT Modell in FAST v7.02 and in Bladed v4.4
Attached a picture of the EF for 1st flw- Blademodes.

The asymmetric Modes behave different in FAST and Bladed.
Especially the regressive mode EF in Bladed is decreasing slower from 6 rpm on than in FAST and for the progressive Mode the other way around.
Does anybody has an idea what the reason could be for this?

The small bumps are not seen in FAST results due to the lack of points in this range.

With best regards,

Simon

Dear Simon,

I’m not sure, but are the operating point rotor speeds at each wind speed from which the linearizations were obtained the same between FAST and Bladed? (Differences in the operating point rotor speed can result in differences in the resulting eigenfrequencies.)

Best regards,

Dear Jason,

Yes, the operation points are almost the same as you can see in the picture.
Are there any other ideas for the differences?

Best regards,

Simon